Techniques proposed in the past for pixel error recovery and post-process improvement due to quantization effects from coding, often used a three stage approach. The first stage provided rough concealment for an entire image frame using an elementary interpolation procedure. The second stage improved the frame by revisiting every erroneous pixel and using neighboring data to select a filter based upon a local spatial, motion, and error classification. Corresponding to each classification, one estimation filter was prepared in advance. The third stage applied a fixed smoothing filter to reduce quantization effects.
Filters prepared in advance severely limit the number of error patterns (missing pixel patterns) that may be considered. To compensate for this, past techniques may have used a sub-optimal rough recovery state. Pixel recovery and pixel improvement being separate processes requires a longer time to process. These present problems.